System for obtaining successive operation of the selecting magnets in crossbar switches



March 7, 1950 K. H. THUNELL ETAL 2,499,542

SYSTEM FOR OBTAINING SUCCESSIVE OPERATION OF THE SELECTING MAGNETS IN CROSSBAR SWITCHES Filed April 6, 1945 5 Sheets-Sheet 1 FiJ mn TBR 5m IVR HR: HR, sm sm, 5701 am, 5111 ,Zrbvezawr K.H.Thwn LL 5 .1). Iii/gran March 7, 1950 K. H. TH ETAL SYSTEM FOR OBTAINING SUCCESSIVE OPERATION OF UNELL THE SELECTING MAGNETS IN CROSSBAR SWITCHES '3 Sheets-Sheet 2 Filed April 6, 1945 IN s E" I? g *5 w v, 02 k IZ'L'U eztboz s TfI/ZI/IZ/GLZ/ .llVzL rezz/ March 7, 1950 K. H. THUNELL ETAL 2,499,542

SYSTEM FOR OBTAINING SUCCESSIVE OPERATION OF THE SELECTING MAGNETS IN CROSSBAR SWITCHES Filed April 6, 1945 5 Sheets-Sheet 3 Patented Mar. 7, 1959 UNITED STATES PATENT" OFFICE SYSTEM FOR OBTAINING SUCCESSIVE OPERATION OF THE SELECTING MAG- NETS IN CROSSBAR SWITCHES" Karl; Harry" Thunell, Nockeby,

and StenDaniel Vigren, Stockholm, Sweden, .assignorspto; TelefonaktiebolagetL M Ericsson, Stockholm, .Sweden, acompany of Sweden ApplicationAprilfi,1945, Serial No. 586,849

5 Claims.

spring groups have certaindisadvantages. It isamong other thingsdifiicult to place the contact.

spring groups adequately fromadust protection view point. Further, eachselecting bar is op.-

erated by two selecting magnets andturnedv tothe one-or the other side by an armature commonto the two selecting magnets, different contact spring groups being actuatedby. the two magnets. By releasing the armature after anoperation to one side, it may turnover to the other side, causing an improper operationof the contact spring set, that is operatedby turning the selecting bar to said other. side. Besides, they. are comparatively costly.

By this invention said-contactspring. groups will be entirely disposed of, as all-contacts necessary for a successive operation of the-selecting magnets are actuated by anoperating magnet and only indicated by the selecting magnets.

According to the invention an operating magnet is provided tobe operated by said current impulses or current break, the systembeing arranged'so that, over field contacts, closedby indication of an actuated selecting magnet, asucceeding selecting magnet is. energized; the indicating member of said selecting magnet is set in indicating positon below the respective field.

contact group when the operating magnet thereafter is released so that the operating 'magnet, on its repeated operation, operates the field contact group which, over its field contacts, closes a circuit for operation ofasucceeding selecting magnet, andso on. Other characteristics of the invention are seenfromithe following description.

To clearly understand the invention it is necessary to observe that, when an operating bar in a cross bar switch-is actuated, the selecting members (fingers) on the selecting bars cannotbe inserted below the contact spring groups on said operatingbar but rest, if moved, resiiently against a lifting spring or corresponding member belonging to the respectivecontact spring group, until the operating bar is released.

The invention will hereinafter. be more closely Sweden May- 17, 1944* describedlwith reference to attached: drawings- Figs. 1,. 2. and.3 show two embodiments thereof for. numerical. setting-,.f0r instance, in group or;

final selectors.

InFig. 1,. STM1T-STM4.are.the selecting mag? netsin a cross bar switch, of which only is shown the supplementary operating magnet HBRM': forv successive. operation of; the; selecting. IMR. is anqimpuise indicatingrelay; TBR a slow-operating se.-called:

magnets. STM1-STM4.

blocking relay, STR a. relay. for disconnectionof the. first operated. selecting. magnet; STM1 and NR: an impulse controlling. relay. All I these re lays have functions/known per se.

Theldiagram is:simplified, only; the circuits and switching elementsrequired for a clear unde standing of the invention being shown.

The system operates principally. as follows.

Atwacallon line L, .theimpulse indicat-ngrelay IMBwis operated; whereby a magnetization circuiti for'relay TBR; isclosed overmake in the switchingacontaot .IJ.IMR. When the first cur.- rent interruption takes place, relay IMR is released; while the relay TBR in known manner. is-

slow releasingrand thus not released. until the switching operation is completed. Onrelay IMR releasing, a, circuit is completed from positive overmake. contact l-'I=B,R,,break contact i-STR,..

winding: on selecting magnet STMo and a wind ing on-rrelay HRrtonegative, whereby STMnZand-HR1 are actuated. Erompositive inthe make contact,

Z- -TBR a circuitais nowcompleted in make con tact l-H-Rrover winding I-HBRM-t0 negative;

Consequently, the operating; magnet HBPUM is operated. Aacircuitt is completed in'contact l- S'IMo;for relayIVR; which is not operated, being.

short-cirouited at contact 2-IMR.. over switching contact l--IVR. At contact i-JI-IBRM-a circuit is :completedfor relay STR wh ch, at its contact l,.breaks theinitial magnetization circuit for selecting magnet STMo which nowreceives holding currentover contact ,3--STl\/lo. Relav- ST-R:

Contact 2--HBB.Mguarantees the operation. of

operating magnet HBRM before: relay IVR' operates which is obtained-by-the-lastsmentioned" HRi andHRa --are. supp1ementary. relays for the: bar setting.

relay being short-circuited at said contact 2- HBRM when the operating magnet HBRM is non-energized. When relay IMR at the following current break is again deenergized relay IVR receives holding current through its winding 11 over contacts IIVR., 2-IMR and 2TBR. The selecting magnet STMi and, in series with it, relay HRz are now energized over contacts l IMR, I-TBR, 2--IVR and 2-STM0. The operating magnet HBRM being operated, indicating member on selecting bar of selecting magnet STM1 cannot be inserted below the field contact group but rests at the moment resiliently against the lifting spring or corresponding member below said field contact group. The magnetization current for the operating magnet HBRM is now interrupted at the make-and-break contact IHRz and when the operating magnet is released the circuit for selecting magnet STMO and relay I-lR1 at contact 3STM0 is interrupted. The selecting magnet STMI and relay HRz remain in operated position as they receive holding current over contacts 3IVR and 2--HR2 and resistance R1. The resistance value of resistances R1R4 is selected so that the respective selecting magnets are not operated by current therethrough but only held in operated position after once having received more powerful make current. Indicating device on the bar of the selecting magnet STM1, by its elastic force, penetrates under the respective multiple contact group.

On release of relay HR1 a circuit is completed for winding IIHBRM over contacts 2-TBR, IHR2 and 3-HR1. Thus the operating magnet HBRM is again operated, thereby operating the field contact group corresponding to selecting magnet STM1. By the field produced by winding IIHBRM having inverse direction to the field from winding IHBRM, full guarantee is given that the operating magnet is released completely during the brief period of time both these windings are de-energized, since inversion of the field takes place. At contact 2STM1 a make circuit is prepared for selecting magnet STM2 and at contact 3-STM1 a holding circuit for selecting magnet STlVh is closed. When relay IMR is again magnetized the holding circuit at contact 2IMR is broken for relay IVR which is then released. At the following release of relay IMR, the magnetization circuit for selecting magnet STMz and relay HR1 at contact l--IMR over contacts l-TBR, 2--IVR and 2-STM1 is formed. When relay HR1 operates a holding circuit is closed for selecting magnet STMz and relay HRI over contacts 3IVR and 2HR1 and resistance R2. Furthermore, the circuit for winding II- I-IBRM at contact 3HR1 is interrupted and selecting magnet STM1 and relay HRz are released when contact 3-STM1 is broken on release of operating magnet I-IBRM. The winding I HBRM is energized over contacts 2TBR, l- HRz and I-IBRM is again operated. The operation described above is repeated if further impulses arrive on the line L.

In a system according to Fig. 2 the supplementary relays HR1 and HRz shown in Fig. l are dispensed with.

At first, as in the system shown in the foregoing figure, the relays IMR and TBR are energized. When relay IMR releases at the first current break, a circuit is completed for selecting magnet STMo at contact l--IMR. over contacts ITBR and l-STR. At the same time a make circuit or relay STR1 at contact 2-STR is closed. Re-

l-HR1 whereby operating magnet lay STR has a longer make time than selecting magnet STMo so as to guarantee its closing before its make circuit is broken at contact l-STR. Selecting magnet STMo remains operated by a circuit over resistance R1 and contacts ISTR and 2TBR. Relay STR receives holding current over contacts 2-STR. and 3TBR, thus remaining operated until termination of the switching operation. On relay STR closing, a circuit is formed at contact 3STR over contacts I- IIWR, ITBR and 2IVR for winding I on operating magnet HBRM which operates and receives holding current over field contact ISTM0. A circuit is prepared for selecting magnet STM1 at contact 2STM0 and a holding circuit is closed for selecting magnet STMD at contact 3-STM0. At contact 4--STM0 a circuit is closed for winding I on relay IVR, which is however kept short-circuited over contacts 3--IVR, 2-IMR and 2TBR as long as relay IMR. is non-energized. When the latter relay on termination of current break operates again, the make circuit is broken for winding IHBRM and the short-circuiting of relay IVR, is removed, said relay thus operating. At the following release of relay IMR the relay IVR receives holding current through its winding II over contacts 3IVR, 2IMR and 2TBR and a circuit is completed for winding l'l on Operating magnet over contact l--IMR, I-TBR, l-STR and 2IVR. When the current over winding IIHBRM is more powerful than the holding current over winding I-HBRM and when the windings counter-act each other, a field inversion occurs in operating magnet HBRM which is thus released and thereupon operates anew. During the time the operating magnet HBRM has non-energized position, the holding circuit is broken for selecting magnet STMo at contact 3 STMo and the indicating member is inserted into the selecting bar corresponding to the selecting magnet STM1 under the respective field contact group. Selecting magnet STM1 is kept operated by current over contacts 2-TBR, IIVR and resistance R2. Further, a circuit is closed for operating magnet HBRM winding II over contacts IHBRM, 3-STR and 2IVR. Contact l-HBRM has for an object to guarantee the closing of the operating magnet, even if relay IMR should be operated before the operating magnet has had time to operate again, thus rendering the system independent, to a certain extent, of the impulse condition of the impulse train. When the operating magnet HBRM operates the field contacts of selecting magnet STM1 are closed. Over contact l-STM1 the operating magnet HBRM receives holding current. Over contact 2STM1 a circuit is prepared for selecting magnet STM2 and, finally, at contact 3- STM1 a holding circuit is closed for selecting magnet STM1. When the relay IMR. again is closed the circuit at contact 2IMR is broken for winding II on relay IVR, which is released. At the now following release of relay IMR a circuit is again completed for winding IHBRM so that field inversion takes place in the operating magnet I-IBRM whereupon theoperation is sim lar to the previously described operation. Contact 2-I-IBRM serves to prevent relay IVR, from operating or relapsing res ectively during the time the operating magnet HBRM is released.

In Fig. 3 magnets STMo, STM1 etc. are selecting magnets in a crossbar switch. the o erating ma nets of which are termed BRMo. BRM1. and BRMQ. Each contact field of the operat ng magnet contains three contact strips S1, S2 and S3.

Contact fieldj ofzoperatingzmagnetrBRlvlocontains fnrthena; fourth suchtstrip; S4... The cwand b.-- wiresof incoming line-here :connectedinzparallel totstrips :S1 .and :82 respectively. in v all the-operating: magnets. Theoutgoinglinesare connectedto the: individual. contacts-on :respective:operatingmag net in such-awaythatctheirraand hewires on op.-= eration of a certain. field: contact. group over respective .stripsisi ancLSa are connected ltotincoma. ing. lineeLi, and; their. c-;-Wir.es:.over'.; theirespective. strip Si..toitest-cdevicesiv ThGZOllt'gOiIlg-IHDGS which. are connected. tozfield Lcontactsacorresponding. to. the. same selectingmagnetform-ainumerical route-i; withinv which nonnumer'ical selection can take place.- Amongst-the out'goingflinese; only one; La, is shownimthefigure; l H

The relay :set-of thezgroup .selecton'isicomposedl of a. test vrelay LYR an impulse: indicating: relay J MR, a slow-acting so-called cut-out relay TBR,

aanumber: indicatingrelayxsMR -andfi aarelay STR for. disconnection-- of the firstzoperatedl selectingv magnet STMOF I A The system operates principally as; follows;

When the-group selector isxcalled, the circuit forthe impulse'indica'ting relay JMR-is- :closed inknown man-ner'oven line 131.. On closingoiirelay' JMR the make circuit for relay TBR at contact I--J1\dR- is closed, said relayi being: slow releasing so that it remains" attracted' although relay J is released and attracted in time-to the numerical impulses; Whenrelay TBR is' attracted a-circuit is completed over contacts-3-'.' TBR; l -BRMt and l-STR for selecting magnet- STMo' which is op erated. On relay JMR; being releasedat begin-- ning of the first impulse a further circuit is closed over contactsZ-JMR, l--T=BR and ISTR for relay SMR which-thusloperates. At contact l- SMR the strip S4 is connected to positive potential.

When the relay JMR at thetermination of the impulse is attracted again, relay STR. is energized by current through its winding 1. over contacts l--JMR and 2-SMR. The make circuit for selecting magnet STMO is broken at contact 4-STR and; for relay. SMR, .atcontact I l-STRi. Both remain however attracted, .the .-selecting; magnet STMo fen-holding currentloverz res-iStanceufmand relay SMR due to delayed action. It is to be observed that the resistances rare so dimensioned that the selecting magnets are not operated in series therewith, but receive sumcient current to remain actuated when once in operated position.

When now, at beginning of the second impulse the relay JlVlZR, is released the make circuit for operating magnet BRMo is closed at contact I- J MR over contacts l--SMR and 2-STR and over the contacts 'l-BRM2 and l-BRMi (contacts in the side spring groups of the operating magnets) connected in series. Operating magnet BRMO is thus operated. Simultaneously relay SMR receives a new magnetization impulse over contacts 2JMR, l-TBR and 3-SMR. When the operating magnet BRMo operates, winding on selection magnet STM1 is connected to strip S4 causing operation of said selecting magnet. Since operating magnet BRMo already is operated the indicating member of said selecting magnet is not inserted below the contact spring group in question. but rests resiliently against the lifting spring available in the contact spring group or against a corresponding member. When t e op- When-now; at termination? of? the: second: pulse relay J MR1. is again: attracted, the-1 circuit for: operating: magnet :BRMe is brokeniat contact 1 l.JlVI R causin'gl'said operatingrmagnetitoibe-re leased. Although the make-circuitfor selecting magnetSTM; is broken at the field contact in the field: contact 1 group correspondingto the selecting rm-agnetzsTMo which field contact cooperates i The operation at further incoming'numeri'cal impulses is entirely similar. to the above described" operation. wherefore any further description hereof may not be necessary.

After termination of thelast' numerical impulse the relay JMR, remains closed, causing-relay circuits are broken for selecting magnets STM wherefore the hereupon followingoperation of the operating magnet BRMc does not cause any selecting magnet to operate. The lastoperated selecting magnet hereafter remains operated irrespective of the position-of theoperating mag-'- net- BRMt sinceit receivesholdingcurrent overcontacts li -SMR and f4-'-STR. The operating magnet BRMo is energized 'anew'by; current over contact 5=--SMR; Its "operation" initiates a'ru'sh movement dur ng whic-hoperating magnets BRM'" successively operate" until-a free-line inthe numerical route appointed 'by the'operated-select ing magnet is found. Theselection-takes place as fol-lows.

By 1 operation of the operatingmagnet BRMd thee-wire of the respective outgoing' line is connected over contact S-BRMi, holding- II STR" andcontact 'l-SMR' to winding on testrelay LYR. Presuming that the lineis'now' engaged, therelay LYR-is not energized; on operation of operating magnet 'B-RMm the" make circuit' for" operating magnet BRM1 is immediately closed over contacts 3-LYR, 2TBR, 8-SMR, and ll-BRMo. On operation of BRM1 the test relay LYR is disconnectedfrom the test conductor of the connected line in order to prevent testing to take place on said line after operation of the operating magnet BRM1. The circuit for operating magnet BRMO is now broken at contact I--BRM1 where instead a holding circuit is closed for BRM1. The test conductor of the now connected line is connectedto test relay LYR over contact 3-BRM2 the operation of which is similar to that of contact 3BRM1. The successively performed operation and release of the operating magnets continues identically tilla free line is found. Hereby the test relay LYR is 75 TBR also releases.

actuated in known manner, the make time of which is briefer than the make time for the operating magnets. The selection time is now stopped by break of a rush circuit at contact 3-LYR whereby the incoming line L1 is connected to the respective outgoing line La. at contacts I-LYR and 2-LYR. Although relay IMR releases relay STR is energized by current through its holding winding II in series with test relay LYR. By the permanent release of relay JMR the relay When the c-wire of the outgoing line Ls, is de-energized by releasing of the communication the relays LYR and STR are released and thus also the operated operating magnet BRM, the holding circuit of which is broken at contact 2-STR.

The above described embodiments are only to be considered as examples to give a more clear understanding of the invention. The invention naturally allows of many variations and modifications without the principle of invention thereby being infringed upon.

We claim:

1. In an automatic telephone system, a cross bar switch and an impulse relay, said cross bar switch including selecting magnets and an operating magnet, an operating bar actuated by the said operating magnet, one contact set on said operating bar for each selecting magnet, one contact in each of said contact sets, when actuated, closing a circuit for energizing a succeeding selecting magnet, means for energizing one of said selecting magnets, means for energizing said operating magnet in dependence upon an impulse from said impulse relay to actuate the contact set for the energized selecting magnet, means for operating said succeeding selecting magnet, means for releasing the first and holding the last energized selecting magnet upon said operating magnet being released and thereafter energized by another impulse from said impulse relay.

2. In an automatic telephone system, a cross bar switch and an impulse relay, said cross bar switch including selecting magnets and an operating magnet, an operating bar actuated by the said operating magnet, one contact set on said operating bar for each selecting magnet, one contact in each of said contact sets, when actuated, closing a circuit for energizing a succeeding selecting magnet, means for energizing one of said selecting magnets by an impulse from said impulse relay, means for energizing said operat- 3. In an automatic telephone system, a cross bar switch and an impulse relay, said cross bar switch including selecting magnets and an operating magnet, an operating bar actuated by the said operating magnet, one contact set on said operating bar for each selecting magnet, one contact in each of said contact sets, when actuated, closing a circuit for energizing a succeeding selecting magnet, means for energizing one of said selecting magnets, means for energizing said operating magnet, in dependence upon an impulse from said impulse relay to actuate the contact set for the energized selecting magnet, means for operating said succeeding selecting magnet, means for releasing the first energized selecting magnet, when said operating magnet is energized by said impulse, and for holding the said succeeding selecting magnet after the termination of said impulse.

4. In an automatic system as described in claim 2, two circuits for actuating the operating magnet, controlled by said impulse relay, a winding for the operating magnet in each of said circuits, said two circuits energizing the operating magnet in opposite directions, means changing said two circuits at th beginning of each impulse from said impulse relay.

5. In an automatic system as described in claim 2, two circuits for actuating the operating magnet,,controlled by said impulse relay, a winding for the operating magnet in each of said circuits, said two circuits energizing the operating magnet in opposite directions, means changing said two circuits after the end of each impulse from said impulse relay.

KARL HARRY THUNELL. STEN DANIEL VIGREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,575,326 From Mar. 2, 1926 2,038,222 King Apr. 21, 1936 2,259,101 Davis Oct. 14, 1941 

